Newly laid sandstone staining... HELP!!

[artfulglv19]

Morning all,

I've just finished laying a Indian sandstone patio - Kandala Grey - It's been stop start over the last 8-9 weeks due to intense rain&not being at home.

It's been laid of a full bed of cement mixed 5-1 with sharp sand which we mixed by hand each time as we knew we'd not be fast enough to pour loads and lay en mass.

We finished this weekend and all looked good and then we planned to seal it all in this weekend and then grout however, some of our tiles are now developing as per the picture some extremely weird staining that looks to be in the tile.

I've washed down with washing up liquid diluted in hot water and also jet washed it all off, and was pretty sure it would to nothing which it's not.

Which leads me on to my question WTF is happening or has happened, can I fix it and will it go away as I can;t seal them in as it is or it's going to most likely remain in place??

I'm really gutted about this as we've spent so so much time on this as we've never laid a patio before so have literally put hours of hard lab our, sweat and swear words into this project.

HELP

 

[footprints]

Might just be drying out after so much rain and green cement, try not to look for a couple of weeks the patio fairies may well come and fix it!
I assume you did lay on a solid base not dabs as dabs can give this effect.

 

[^woody^]

Yes that looks like dabs and not a full solid bed.

But the whiter salt-looking marks will need to weather out over months - dont try and wash them off as you are washing them back in. You'd be wise not to seal it yet and give it at least one year (one winter) to weather.

 

[artfulglv19]

It's a full solid bed under each slab, we only had to re lay a couple as for some reason they had not fully taken, e.g it rocked between two corners.

Could it be caused if it had air pockets?? I mean we knocked them all down with a mallet all over, along sides, each corner until they were then level with the slabs next to them.

We wanted to grout so I suppose again we can't do this until it's sealed either to avoid any grout staining the tiles is that fair to assume?

 

[Monty..234]

It is the slabs sucking the moisture through from the cement i know yo have laid on full beds but this normally happens when they are just spotted, it may well disappear in time, I work for a landscaper and we have laid this loads and only ever had the problem once we now a sealant painted on the back to prevent this

 

[artfulglv19]

Morning Monty,

Yeah you're right as you well know... we Didn't know about sealing them until we started our second end of the patio so now we paint on some primer before and let that soak in as well and then do a primer/cement slurry painted on as well before laying!

Annoyingly we learnt by our mistakes... Thanks for the reply though!

Neil